Saturday, August 23, 2014

A few days before I set off on my travels, I caught a train to a top secret location to take part in a short film about opinion polls in the referendum campaign. It's now available on YouTube, and you can watch it HERE.

I'm flying blind with this one, because I haven't actually seen it yet - I can't watch videos on my mobile! (Or not without huge difficulty.)

That's another record high for Yes from the No-friendly firm YouGov. The previous record was 43%, and if memory serves me right that was only reached once.

If this was Ipsos-Mori, the figures for definite voters would of course be used as the headline numbers, on the basis that there is a strong correlation between the number of people who tell polling firms they are absolutely certain to vote, and the actual turnout in elections. When you look at it that way, there is now - for the time being at least - a degree of convergence between YouGov and other pollsters, in spite of the notorious "Kellner Correction". YouGov's turnout-filtered Yes figure of 44% is very similar to ICM's unrounded figure of 44.6% (which admittedly is based on a more complex form of turnout weighting). Remarkably, all six pollsters are currently showing a Yes vote of at least 42%.

But is there any way the No side can convince themselves that the surge for Yes seen in the three polls over recent days isn't really happening? Well, with a bit of effort you can construct a case. Although ICM showed a 2% swing, Yes were starting from an unusually low base in the previous poll, so you could argue that the change was an artifact of the margin of error. Panelbase have shown a return to an all-time high for Yes that was reached in a previous poll, so you could argue that the slight dip in the interim was also a margin of error effect, and that nothing has really changed. However, that ignores the suspicion that the net effect of Panelbase's recent methodological changes is No-friendly, and that the new poll is in real terms better for Yes than anything that has gone before.

As for YouGov, although they're showing an outright record high for Yes, you could pray in aid the fact that they have recently made a mildly Yes-friendly methodological change (country of birth weighting), and that on a pound-for-pound comparison the new poll is no better for Yes than the previous high of 42% in the poll for Channel 4 News in the spring. The problem with that argument, though, is that there have been no fewer than three YouGov polls in the interim which have left the distinct impression that the 42% finding was an aberration.

So the argument that there has been no change is a bit convoluted, to say the least. Professor Curtice said yesterday that we cannot rule out the possibility that there has been more movement to Yes. I'd put it the other way round - the balance of probability is that there has been a swing to Yes, but because ICM's figures weren't quite as good as the others, and because of the uncertainties surrounding the methodological tweaks made by Panelbase and YouGov, we can't completely exclude the possibility of an unchanged position. What we sure as hell CAN exclude the possibility of, though, is a post-debate boost for No.

Incidentally, someone asked on the previous thread if YouGov ask for party political voting intentions before referendum voting intentions. The answer is yes, and they also seem to switch back and forth between asking for Westminster voting intention first, and going straight to Holyrood voting intention. In theory, this is bad practice which could distort the referendum findings. However, when Panelbase stopped asking for the party political answers first (after being criticised for it by Curtice), it didn't appear to make much difference.

* * *

REQUIRED SWINGS

Swing required for 1 out of 6 pollsters to show Yes ahead or level : 2.0%

Swing required for 2 out of 6 pollsters to show Yes ahead or level : 4.5%

Swing required for 5 out of 6 pollsters to show Yes ahead or level : 6.5%

* * *

SCOT GOES POP POLL OF POLLS

MEAN AVERAGE (excluding Don't Knows) :

Yes 43.6% (+0.6)No 56.4% (-0.6)

MEAN AVERAGE (not excluding Don't Knows) :

Yes 37.8% (+0.5)No 48.8% (-0.7)

MEDIAN AVERAGE (excluding Don't Knows) :

Yes 42.6% (+0.1)No 57.4% (-0.1)

(The Poll of Polls is based on a rolling average of the most recent poll from each of the pollsters that have been active in the referendum campaign since September 2013, and that adhere to British Polling Council rules. At present, there are six - YouGov, TNS-BMRB, Survation, Panelbase, Ipsos-Mori and ICM. Whenever a new poll is published, it replaces the last poll from the same company in the sample. Changes in the Poll of Polls are generally glacial in nature due to the fact that only a small portion of the sample is updated each time.)

Sunday, August 17, 2014

Thanks to Denise for pointing me in the direction of Kevin Pringle's tweet, revealing that YouGov - the most No-friendly pollster of the lot - is about to publish their best poll for Yes of the campaign so far. There are two ways of interpreting that - it could mean the best poll with Don't Knows included (which would imply a Yes vote of 38% or above, and a No vote of anything), or it could mean the best with Don't Knows excluded (which would imply a Yes vote of at least 43%, and a gap of no worse than 43/57). Obviously the latter would be better, but either way it's going to transform our perception of the polling landscape after three successive underwhelming YouGov polls.Taken in conjunction with the pro-Yes swings in the ICM and Panelbase polls, it will bolster the perception that there is now real momentum behind Yes.

I'm travelling on the continent at the moment, but I'll update with the figures when I get a chance.

The datasets aren't out yet for either poll, so I don't know the unrounded figures, or if there have been any further methodological changes. Most importantly, I'm wondering if ICM have joined the new orthodoxy of weighting by country of birth? If they haven't, there's every reason to assume that they are underestimating the Yes vote, because on previous occasions when they have asked for respondents' country of birth, it's turned out there are significantly too many English-born people in their sample, and of course that is a strong predictor of a No vote.

There's no such problem with Panelbase, the firm that in their last poll started the long-overdue trend towards country of birth weighting. However, they coupled that with a No-friendly methodological change (a degree of weighting by European Parliament recalled vote), which in my view may have more than offset the benefit for Yes. That's just a guess, though, and it will have to remain so, because Panelbase have indicated that they will not provide figures using the old methodology for comparison. If I'm right, it means that Yes have effectively reached a new all-time high with Panelbase.

Incidentally, there's a qualitative difference between the two methodological changes Panelbase have made. The Yes-friendly change (country of birth weighting) has logic behind it that is absolutely inescapable - we know roughly how many English-born people there are in Scotland, so leaving too many in the sample is bound to skew the result. By contrast, the No-friendly change of weighting on a combination of recalled Holyrood and European Parliament vote seems merely to be based on inspired guesswork about what 'feels right'.

Question : If Panelbase had ONLY introduced country of birth weighting, and hadn't changed the weightings for recalled vote, is it possible that Yes would be in the lead in this poll, or level? It's an intriguing thought...

Unlike Panelbase, ICM aren't showing Yes on an all-time high - although the Yes vote is up markedly on the last poll, that takes it back to a position that is more or less average for the year so far. So there are two possibilities - either the Yes vote has increased in spite of (or perhaps because of) what happened in the leaders' debate, or the change is margin of error noise masking a static position. Either way, we now have sufficient evidence from multiple polls to effectively extinguish the delusion that there was a pro-No bounce following the debate - it looks highly likely that the Survation poll led us up the garden path on that one.

Although the No campaign can draw some comfort from the fact that undecided respondents break more for No when pressed by ICM (a radically different finding from many other surveys), I'd caution you to ignore John Curtice's nonsensical claim that three-quarters of undecideds are on the No end of Yes Scotland's preferred 1-10 scale. All he tells us is that those people are on 5 or below - and doesn't say anything about how many of them are on exactly 5. As I've pointed out many times before, Yes Scotland do indeed use a 1-10 scale, but it's highly unlikely that they're stupid enough to interpret a 5 as being on the No end of that scale - most people who say they're a 5 regard themselves as being exactly in the middle.

Curtice has made a song and dance about how both this poll and the last one from ICM have failed to provide evidence for Yes Scotland's claim that public opinion is more favourable for Yes when measured by the 1-10 scale. The issue of how to interpret 5s obviously muddies the waters here, but either way Curtice's analysis ignores the findings of the Economic and Social Research Council study, for which ICM conducted the fieldwork, and which used a modified form of the scale. That unambiguously showed that there were more people leaning Yes than you'd expect to find based on the results of the headline question.

UPDATE : Ignore the suggestion from an anonymous poster in the comments section below that the Panelbase poll was tainted by the asking of leading questions prior to the main referendum question - that was quite simply not the case. Professor Curtice has confirmed that the methodology was identical to the one Panelbase used for their last Sunday Times poll.

* * *

REQUIRED SWINGS

Swing required for 1 out of 6 pollsters to show Yes ahead or level : 2.0%

Swing required for 2 out of 6 pollsters to show Yes ahead or level : 4.5%

Swing required for 4 out of 6 pollsters to show Yes ahead or level : 6.5%

* * *

SCOT GOES POP POLL OF POLLS

MEAN AVERAGE (excluding Don't Knows) :

Yes 43.0%(+0.6)No 57.0% (-0.6)

MEAN AVERAGE (not excluding Don't Knows) :

Yes 37.3%(+0.8)No 49.5% (n/c)

MEDIAN AVERAGE (excluding Don't Knows) :

Yes 42.5% (n/c)No 57.5% (n/c)

(The Poll of Polls is based on a rolling average of the most recent poll from each of the pollsters that have been active in the referendum campaign since September 2013, and that adhere to British Polling Council rules. At present, there are six - YouGov, TNS-BMRB, Survation, Panelbase, Ipsos-Mori and ICM. Whenever a new poll is published, it replaces the last poll from the same company in the sample. Changes in the Poll of Polls are generally glacial in nature due to the fact that only a small portion of the sample is updated each time.)